Both brothers were members of St.Stephen's Cathedral Choir in Vienna, and with Joseph being 5 years older, Michael became a favorite boy soprano after his brother's voice broke. Michael was a more diligent student than his brother and shortly after he left the choir he became Kappelmeister at Nagyvárad and finally in 1762 at Salzburg where he remained for 43 years. He knew the Mozarts in Salzburg and Wolfgang was an admirer of his music, while Mozart's father Leopold thought Michael Haydn drank too much, the accusation perhaps an attempt to discredit Michael's reputation for a position his son was also working towards. Michael and Joseph remained close and the older brother also thought highly of Michael's music. Michael was also a teacher who counted among his pupils Carl von Weber and Anton Diabelli.
The younger Haydn's religious music is thought to be his best work, but he wrote in all the genre of the time, including over 43 symphonies. Most of Haydn's symphonies are in the fast-slow-fast movement scheme, but he also wrote some with 4 movements.
Michael Haydn never compiled a catalog of his works, nor were many of them published in his lifetime. There have been three major attempts to catalog his works which has led to confusing numbering systems. As well as being known as Symphony No. 23 In D Major, this symphony is also known as P. 43 (after musicologist Lother Perger's catalog), S. 22 & 23 (after Charles Sherman's 1982 catalog which to add to the confusion originally numbered the work 22, and then was adjusted to number 23) and MH. 287 (another effort by Charles Sherman along with T. Donley Thomas done in 1992). Bewildering as all of that is, it must be said that the parts of this same symphony were thought to be by Mozart for many years. Ludwig von Köchel who catalogued Mozart's works in the middle of the 19th century had a manuscript of the symphony that had the first 45 measures of the 3rd movement copied out in Mozart's handwriting, so Köchel made the assumption it was a work by Mozart and numbered it Symphony No. 25, K.291.
Symphony No. 23 In D Major has three movements and is scored for 2 oboes, 2 bassoons 2 horns, strings and continuo:
I. Allegro assai - This symphony was written in 1779 in Salzburg and Haydn follows sonata in the first movement. A bright fanfare-like theme begins the movement. This theme leads directly to different sections and motives until a short secondary theme appears. A chattering motive in the violins that has already appeared rounds off the exposition. The fragment of the first theme leads off the development section and is thrown about in different keys until transitional material leads to the recapitulation. Themes go through the usual modulations and leads to a short coda that begins with the chattering violins motive and ends with a last comment on the a fragment of the first motive.
II. Andantino - Michael Haydn's slow movements seldom were in minor keys, with this being one of them. The key is D minor but it changes to D major in the middle of the movement. The music moves at a steady pace, is seasoned with syncopation and a good blend of strings and winds in the middle section. A short dialog for winds and strings brings the movement to a close.
III. Finale: Presto ma non troppo - It was the first 45 measures of this movement in Mozart's hand that led to the false attribution of the symphony to Mozart. The movement is fugal, and begins with a subject in 4 whole notes. Perhaps the reason Mozart copied out the older composer's music was to study the fugal form the older composer used, for Mozart's 14th String Quartet in G Major K.387 is fugal and also begins with a subject of 4 whole notes. The fugue ripples through the orchestra with episodes between the reappearance of the subject in a kind of fugal rondo. A final appearance of the subject brings this well-crafted and tuneful symphony to a close.